INDEX. 



597- 



Pollen, its fertilising power impaired by 

 low temperature, 110 



. its formation induced by high 



temperature, 108 



Populus monilifera, instance of extending 

 its roots, 19 



Potash as a manure, 554 



employed to promote germina- 



tion, 236 

 Potato, curl in the leaves of, 99 

 renewal of, by seed, 474 



size and weight of, increased by 



preventing the formation of 

 flowers and fruit, 487 



tubers of early varieties, their ap- 



propriation of nutritive matter, 

 242 



unequal period of its maturity 



from different eyes, 267 

 Potatoes, greater weight of, obtained 

 from sets than from whole 

 tubers, 266 



propagation of, from eyes, 267 



Pots, double, for plants, 436 



effects produced by, when plants are 



suffered to remain too long in, 440 



for plants, their drainage, 170 



importance of being well drained, 



and mode of effecting it, 438 

 importance of the end of the out- 

 ting touching the bottom of, 286 



necessity of their being proportioned 



to the size of the plants, 441 

 need not be made of porous mate- 

 rial, 444 



suggestions for the improvement of, 



432 



suited for cuttings, 288 



Potting, 431 



cases in which it may be advan- 



tageously dispensed with, 432 



objects attained by, 431 



Precautions to be observed in the 



striking of leaves, 277 

 Preservation of races by seed, 463 

 Flicking out of seedlings, 432 

 Principles upon which the operations of 



horticulture essentially depend, 132 

 Productiveness, 94 



Propagation, by buddingandgrafting, only 

 successful within certain 

 limits of affinity, 346 



by cuttings, 281 



by cuttings of roots, 282 



by division, not a cause of 



disease, 270 



by eyes, 264 



by eyes and cuttings, diffe- 

 rence of, from budding 

 and grafting, 304 



Propagation, by knaurs or uovoU, 268 



by knots or excrescences, 267 



by layers or suckers, 301 



by leaves, 80, 266, 271 



by roots, depends on the 



formation of adventitious 



buds, 30 



by runners, 473 



by scales, 273 



by seeds, 464 



■ its objects, 304 



its rationale explained, 285 



natural mode of, by various 



plants, 473 

 Protection afforded by walls, 186 

 Protothall, 11 

 Pruning, 361, 400 



considerations necessary to be 



observed in, 364 



evergreens, 420 



for flowers or fruitj 



for timber, 395 



good and bad, illustrated, 373 



injury o&casioned by, when 



carried to excess, 408 

 its effects, 71, 73, 366 



its objects, 362 



of roots, 367 



of shrubberies, 419 



of transplanted trees, 366 



■ practice of, 373 



principles of, 362 



seasons for, 365, 419 



Pterooarpus marsupium, facility with 



which it may 

 be increased, 

 284 



remarkable in- 

 stance of vi- 

 tality in cut- 

 tings of, 284 



Puddling round transplanted trees not 

 always necessary, and often 

 injurious, 462 



substitute for, 462 



Pyramid pear-trees, French method of 



managing, 378 



QniNOE-tree, mode of pruning, 379 



Eaohs of plants, accidental alterations in, 

 474 



are said to wear out, 471 



degeneracy of, negatived, 



476 



improved, suddenly re- 

 vert to their wild state, 

 504 



improveiuent of, 465, 



481 



